High-power laser systems are being developed for a number of military and commercial applications. One example use of high-power laser systems involves capturing images of remote objects, such as drones or other aircraft. Another example use of high-power laser systems involves focusing high-power lasers to achieve high energy accumulation on remote objects to produce certain effects. In these and other types of systems, beam directors are often needed to track moving objects and to direct or focus laser beams onto the moving objects. This typically occurs in the presence of atmospheric disturbances, aero-optic effects, and other disturbances.
Conventional beam directors often use “on-axis” telescope designs in which a secondary mirror is placed physically in front of a primary mirror. Such telescopes are referred to as “obscured” telescopes since the central portion of the primary mirror is obscured by the secondary mirror. While suitable for use at low laser powers, on-axis telescope designs typically require accommodations for use at high laser powers to avoid illuminating the secondary mirror and its associated support structures to high-power laser beams, which can damage or degrade the performance of those components. Moreover, the obscuration associated with on-axis telescopes reduces the effectiveness of focused beams on remote objects.
Conventional laser imaging systems and high energy laser (HEL) focusing may also require the use of a “beacon” laser to be focused to a small spot on the object and a sensor to estimate the wavefront error of the optical path from the object to the sensor. However, this approach is complicated by the need for a separate beacon laser, as well as by blurring of the outgoing beacon laser beam by atmospheric disturbances, aero-optic effects, and other disturbances.